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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 842
UG585 (v1.11) September 27, 2016
Appendix B: Register Details
Register (ddrc) Two_rank_cfg
reg_ddrc_burst8_refres
h
6:4 rw 0x0 Refresh timeout. Programmed value plus one will
be the number of refresh timeouts that will be
allowed to accumulate before traffic is blocked
and the refreshes are forced to execute. Closing
pages to perform a refresh is a one-time penalty
that must be paid for each group of refreshes;
therefore, performing refreshes in a burst reduces
the per-refresh penalty of these page closings.
Higher numbers for burst_of_N_refresh slightly
increases DRAM utilization; lower numbers
decreases the worst-case latency associated with
refreshes.
0: single refresh
1: burst-of-2
...
7: burst-of-8 refresh
reg_ddrc_data_bus_wi
dth
3:2 rw 0x0 DDR bus width control
00: 32-bit
01: 16-bit
1x: reserved
reg_ddrc_powerdown_
en
1 rw 0x0 Controller power down control. Update during
normal operation. Enable the controller to
powerdown after it becomes idle.
Dynamic Bit Field.
0: disable
1: enable
reg_ddrc_soft_rstb 0 rw 0x0 Active low soft reset. Update during normal
operation.
0: Resets the controller
1: Takes the controller out of reset.
Dynamic Bit Field.
Note: Software changes DRAM controller register
values only when the controller is in the reset
state, except for bit fields that can be dymanically
updated.
Name Two_rank_cfg
Relative Address 0x00000004
Absolute Address 0xF8006004
Width 29 bits
Access Type rw
Field Name Bits Type Reset Value Description